U.S. and Other Powers Aren't Leading the World

Ian Bremmer and Mohamed El-Erian argue that a leadership vacuum is contributing to geopolitical woes.

Editor's Note: Bremmer is president and founder of Eurasia Group, a political risk research and consulting firm. El-Erian, the former CEO of Pimco, is currently chief economic advisor to Allianz, a German-based financial services company and Pimco's corporate parent.

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